Determination of puerarin in rat plasma by rapid resolution liquid chromatography tandem mass spectrometry in positive ionization mode

A highly sensitive and specific method of rapid resolution liquid chromatography tandem mass spectrometry (RRLC–MS/MS) in positive ionization mode has been developed and validated for pharmacokinetic study of puerarin in rat plasma. Chromatography was carried out on a Zorbax XDB C18 reversed-phase column using a mobile phase comprising a mixture of methanol and 0.05% acetic acid in water (35:65, v/v) with a flow rate of 0.3 mL/min from 0 min to 5.4 min and then 0.6 mL/min from 5.41 min to 12 min. The mass spectrometer operated in ESI positive ionization mode. Multiple reaction monitoring (MRM) was used to measure puerarin and tectoridin (internal standard). The method was sensitive with a detection limit of 0.33 ng/mL. A good linear response was observed over a range of 10–2000 ng/mL in rat plasma. The inter- and intra-day precision ranged from 2.97% to 7.52% and accuracy from 93.70% to 101.60%. This validated method was applied successfully to a pharmacokinetic study in rat plasma after intravenous administration of puerarin. The main pharmacokinetic parameters were as follows: AUC0→t 45.37 ± 13.19 (mg h/L), AUC0→∞ 47.03 ± 14.78 (mg h/L), MRT 1.03 ± 0.46 (h), T1/2 1.31 ± 0.31 (h), Vss 0.09 ± 0.02 (L), Vz 0.17 ± 0.04 (L), Cl 0.10 ± 0.04 (L/h).